Effects of Inspiratory vs Expiratory Breath-Hold on Lung Perfusion Measured by EIT Saline Indicator Method: A Self-Controlled Study

December 23, 2025 updated by: Shanghai Zhongshan Hospital

Electrical Impedance Tomography Saline Indicator Technique for Assessing Differences in Lung Perfusion Between Inspiratory and Expiratory Breath-Hold Phases: A Prospective Self-Controlled Study

This study aims to compare lung perfusion distribution between inspiratory breath-hold and expiratory breath-hold phases using the saline indicator method combined with electrical impedance tomography (EIT). A self-controlled crossover design will be used in which each participant undergoes both breath-hold conditions with standardized rapid intravenous saline injections. The primary objective is to evaluate changes in global and regional pulmonary perfusion under different lung volume states. The findings may improve understanding of perfusion redistribution with lung inflation and support optimized ventilatory strategies in clinical practice.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Electrical impedance tomography (EIT) with saline bolus injection is a noninvasive technique capable of generating real-time regional lung perfusion images based on transient impedance changes. Lung perfusion is highly dependent on lung volume, vascular resistance, and gravity, yet quantitative bedside evaluation remains limited.

This prospective self-controlled study investigates the differences in lung perfusion between inspiratory breath-hold (near total lung capacity) and expiratory breath-hold (near functional residual capacity). Each participant will undergo two standardized procedures: (1) expiratory breath-hold followed by a rapid intravenous injection of saline, and (2) inspiratory breath-hold followed by the same injection protocol. The order will be randomized.

Perfusion images will be reconstructed using time-impedance curves derived from saline indicator dilution. Regional perfusion parameters, including dependent vs nondependent zones and global perfusion distribution, will be compared between the two phases.

This study may provide foundational physiological evidence for understanding perfusion redistribution across lung volumes and support the clinical application of EIT in respiratory monitoring, ventilatory management, and rehabilitation in critically ill patients.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
100

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Age 18 to 65 years
  • Able to provide written informed consent
  • Able to perform standardized inspiratory and expiratory breath-hold maneuvers for at least 8 seconds
  • No known acute cardiopulmonary disease
  • Suitable for noninvasive electrical impedance tomography monitoring and intravenous saline administration

Exclusion Criteria:

  • Known severe cardiopulmonary disease (e.g., advanced chronic obstructive pulmonary disease, severe pulmonary hypertension, or heart failure)
  • Hemodynamic instability or clinically significant cardiac arrhythmia
  • Contraindication to intravenous saline administration or fluid bolus
  • Pregnancy or breastfeeding
  • Skin conditions or chest wall abnormalities preventing proper placement of EIT electrodes

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Diagnostic
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Single Group - Self-Controlled
Procedure: Electrical Impedance Tomography Saline Indicator Procedure
Participants undergo continuous electrical impedance tomography (EIT) monitoring with a circumferential electrode belt placed around the thorax. During the procedure, participants perform standardized inspiratory and expiratory breath-hold maneuvers. At each breath-hold phase, a rapid intravenous bolus of sterile saline (10-20 mL) is administered, followed by a saline flush, to generate transient impedance changes for lung perfusion imaging using the saline indicator technique. EIT data are recorded continuously before, during, and after each saline injection. Each participant undergoes both breath-hold conditions and serves as their own control.
Device: Electrical Impedance Tomography Device
An FDA-cleared electrical impedance tomography (EIT) device is used to noninvasively monitor thoracic impedance changes during the study procedures. The device is used solely for physiological monitoring and image acquisition and is not being evaluated for safety, performance, or a new indication.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Global Lung Perfusion Distribution
Time Frame: During the study procedure (within 1 hour)
Quantitative assessment of global lung perfusion distribution derived from saline-induced impedance changes measured by electrical impedance tomography during inspiratory and expiratory breath-hold phases. Global perfusion is expressed as the percentage contribution of regional perfusion relative to total lung perfusion.
During the study procedure (within 1 hour)

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Global Lung Perfusion Heterogeneity Index
Time Frame: During the study procedure (within 1 hour)
Spatial heterogeneity of lung perfusion quantified using a perfusion heterogeneity index derived from regional perfusion maps obtained with the electrical impedance tomography saline indicator technique.
During the study procedure (within 1 hour)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Shanghai Zhongshan Hospital

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
January 1, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
January 1, 2027

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
January 1, 2028

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
December 12, 2025

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
December 23, 2025

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
December 26, 2025

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
December 26, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
December 23, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
December 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • EIT-BH-PERF-2025-01

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

Yes

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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